The present invention relates to axial gap dynamo electric machines and more particularly, in improvements of the bearings thereof.
Axial gap dynamo electric machines deploy stators and rotators that are generally in the shape of parallel and adjacent planar discs, with one of more rotators attached to an axle that passes though the center of each disk.
The stators comprises multiple windings that generally wrap across the radial direction of the disc. A Lorenz force is generated by the interaction with magnets arranged along the periphery of the rotor disc. A more detailed description of this technology can be found in the U.S. Pat. Nos. 4,567,391; 4,578, 610; 5,982,069; and 5,744,896, all of which are incorporated herein by reference.
Axial gap EDM's are ideally suitable for Vertical Axis Wind Turbine (VAWT) designs. VAWT offers a number of advantages over conventional Horizontal Axis Wind Turbine (HAWT), such as lower maintenance costs and increased durability and reliability. VAWT installations are believed to present a significantly lower hazard to migrating birds as HAWT systems, as well as require a lower cost and less obtrusive support tower due the axial symmetry of the generator and turbine blades. One such VWAT is disclosed in U.S. Pat. No. 5,531,567, which is incorporated herein by reference. A magnetically levitated VWAT is disclosed in U.S. Pat. No. 7,303,369, which is also incorporated herein by reference.
While VAWT systems are also more economically viable in remote locations than 100+ kW HAWT systems, there is an ongoing need to improve the efficiency of such machines as well as lower their capital cost so reduce the cost of electrical power derived from this renewable energy resource, and make small to medium size facilities more economically viable for say small communities or even the individual homeowner.
Accordingly, it is a general object of the invention to improve the quality and economic viability of large scale axial gap electro-dynamo machines (EDM) for use as generators and motors.
It is a more specific object of the invention to provide an axial gap EDM with efficient magnetic bearings to minimize the need for bearing replacement.
It is a further objective of the invention to provide the above benefits in a cost effective manner and not unduly complicate or compromise the overall design and function of the EDM.